Fix some static member emits

lib/runtime/dart/convert.js

 var convert;
 (function(exports) {
   'use strict';
   let ASCII = dart.const(new AsciiCodec());
   let _ASCII_MASK = 127;
   let _allowInvalid = Symbol('_allowInvalid');
   let Codec$ = dart.generic(function(S, T) {
     class Codec extends core.Object {
       Codec() {
       }
@@ skipping 469 matching lines @@
       }
       startChunkedConversion(sink) {
         return this[_first].startChunkedConversion(this[_second].startChunkedConversion(sink));
       }
     }
     return _FusedConverter;
   });
   let _FusedConverter = _FusedConverter$();
   let HTML_ESCAPE = dart.const(new HtmlEscape());
   let _name = Symbol('_name');
-  let _ = Symbol('_');
   class HtmlEscapeMode extends core.Object {
     _(name, escapeLtGt, escapeQuot, escapeApos, escapeSlash) {
       this[_name] = name;
       this.escapeLtGt = escapeLtGt;
       this.escapeQuot = escapeQuot;
       this.escapeApos = escapeApos;
       this.escapeSlash = escapeSlash;
     }
     toString() {
       return this[_name];
     }
   }
   dart.defineNamedConstructor(HtmlEscapeMode, '_');
-  HtmlEscapeMode.UNKNOWN = dart.const(new HtmlEscapeMode[_]('unknown', true, true, true, true));
-  HtmlEscapeMode.ATTRIBUTE = dart.const(new HtmlEscapeMode[_]('attribute', false, true, false, false));
-  HtmlEscapeMode.ELEMENT = dart.const(new HtmlEscapeMode[_]('element', true, false, false, true));
+  HtmlEscapeMode.UNKNOWN = dart.const(new HtmlEscapeMode._('unknown', true, true, true, true));
+  HtmlEscapeMode.ATTRIBUTE = dart.const(new HtmlEscapeMode._('attribute', false, true, false, false));
+  HtmlEscapeMode.ELEMENT = dart.const(new HtmlEscapeMode._('element', true, false, false, true));
   let _convert = Symbol('_convert');
   class HtmlEscape extends Converter$(core.String, core.String) {
     HtmlEscape(mode) {
       if (mode === void 0)
         mode = HtmlEscapeMode.UNKNOWN;
       this.mode = mode;
       super.Converter();
     }
     convert(text) {
       let val = this[_convert](text, 0, text.length);
@@ skipping 1893 matching lines @@
   exports.LineSplitter = LineSplitter;
   exports.StringConversionSink = StringConversionSink;
   exports.ClosableStringSink = ClosableStringSink;
   exports.UNICODE_REPLACEMENT_CHARACTER_RUNE = UNICODE_REPLACEMENT_CHARACTER_RUNE;
   exports.UNICODE_BOM_CHARACTER_RUNE = UNICODE_BOM_CHARACTER_RUNE;
   exports.UTF8 = UTF8;
   exports.Utf8Codec = Utf8Codec;
   exports.Utf8Encoder = Utf8Encoder;
   exports.Utf8Decoder = Utf8Decoder;
 })(convert || (convert = {}));